Technical Field
The present invention relates to semiconductor devices and processing, and more particularly to devices and methods for forming III-V materials on a silicon based wafer while avoiding stress and cracking.
Description of the Related Art
Many high frequency and high performance devices are employed using GaN and GaAs substrate materials. However, forming substrates from these materials tends to be more expensive than employing Si wafers and Si processing techniques. The cost of substrates becomes a bottleneck to the wide scale adoption of the substrate material for these high performance discrete devices. In addition, conventional substrates, such as sapphire and silicon carbide are expensive and have limited availability in larger diameters (i.e., these are typically limited to 4-inch substrates).
Silicon remains more moderate in cost and can provide larger diameter substrates. However, lattice and thermal mismatch between Si and GaN is on the order of 50%. These mismatches can lead to cracking issues for regrown GaN on Si wafers.